It is considered that the main lesion of Alzheimer's disease is degeneration and defluvium of cholinergic neurons. At present, a cholinesterase inhibitor or a muscalinic receptor agonist is used for the treatment of said disease. Such a medicament alleviates dementia symptomatically but cannot stop or retard the progress of the morbidity. There has also been made an attempt to treat Alzheimer's disease by administering a nerve growth factor (NGF) into the brain. NGF is expected to suppress degeneration and defluvium of neurons due to its neuron growth action, thereby terminating or retarding the progress of dementia. However, since NGF is a protein having a molecular weight of 12,000, it cannot pass through the blood-brain barrier and its administration route is confined only to intraventricular administration, which is not practical for the treatment of human beings. If there is such compound that exhibits an NGF-like action and has a molecular weight low enough to pass through the blood-brain barrier or such compound that can enhance the synthesis of NGF in the brain, it will be promising as a remedy effective for treating Alzheimer's dementia.
Based on such an idea, a substance which promotes and/or reinforces production of NGF has been searched, and it has been proved that long-chain aliphatic alcohols such as n-hexacosanol stimulate nerve growth factor in vitro and can pass through the blood-brain barrier in vivo (Japanese Patent Application Laid-Open No. 502167/1992).